<template>
  <div class="pagination">
    <button :disabled="pageNo == 1" @click="$emit('getPageNo', pageNo - 1)">
      上一页
    </button>
    
    <button
      v-if="startNumAndendNum.start > 1"
      @click="$emit('getPageNo', 1)"
      :class="{ active: pageNo == 1 }"
    >
      1
    </button>
    <button v-if="startNumAndendNum.start > 2">.....</button>



  
    <button
      v-for="(page, index) in startNumAndendNum.end"
      :key="index" v-if="page >= startNumAndendNum.start"
      @click="$emit('getPageNo', page)"
      :class="{ active: pageNo == page }"
    >
      {{ page }}
    </button>




    <!-- 这里比较难理解 条件成立：就是当前总页数-1后 还大于当前end值都是需要...的 反之不需要...-->
    <button v-if="startNumAndendNum.end < totalPage - 1">......</button>
    <!-- 后半部依赖于end进行显示隐藏 可以自己慢慢调试即可 -->
    <button
      v-if="startNumAndendNum.end < totalPage"
      @click="$emit('getPageNo', totalPage)"
    >
      {{ totalPage }}
    </button>


    <button
      :disabled="pageNo == totalPage"
      @click="$emit('getPageNo', pageNo + 1)"
    >
      下一页
    </button>


    <button v-trigger @click="$emit('getPageNo', pageNo)">共{{ total }}数据</button>
  </div>
</template>

<script>
export default {
  name: "MyPagination",
  props: ["pageNo", "pageSize", "total", "continues"],
 
  computed: {
   
    totalPage() {
      return Math.ceil(this.total / this.pageSize);
    },
   
    startNumAndendNum() {
   
      let start = 0,
        end = 0;
      let { pageNo, totalPage, continues } = this;
      
      if (continues > totalPage) {
       
        start = 1;
        end = totalPage;
      } else {
      
        start = pageNo - parseInt(continues / 2);
      
        end = Number(pageNo) + Number(parseInt(continues / 2));

       
        if (start < 1) {
          start = 1; //修正为1
          end = Number(continues); 
        }
        
        if (end > totalPage) {
          end = Number(totalPage); 
          start = totalPage - continues + 1; 
        }
      }
      
      return { start, end };
    },
    
  },
  directives:{
    trigger:{
      inserted(el,binging){
        //console.log("触发");
        el.click();
      }
    }
  }
};
</script>
<style lang="less" scoped>
.pagination {
  text-align: center;
  button {
    margin: 0 5px;
    background-color: #f4f4f5;
    color: #606266;
    outline: none;
    border-radius: 2px;
    padding: 0 4px;
    vertical-align: top;
    display: inline-block;
    font-size: 13px;
    min-width: 35.5px;
    height: 28px;
    line-height: 28px;
    cursor: pointer;
    box-sizing: border-box;
    text-align: center;
    border: 0;

    &[disabled] {
      color: #c0c4cc;
      cursor: not-allowed;
    }

    &.active {
      cursor: not-allowed;
      background-color: #409eff;
      color: #fff;
    }
  }
}
.active {
  background-color: skyblue;
}
</style>

  